Dogs and cats getting along?

I would leave these two to sort things out. Cats have an amazing way of defending themselves against dogs. They are way faster and agile, not to mention their claws and teeth are quite formidable weapons as well. The pup will learn its limits with the cat and the cat can't really cause damage (other than superficial) to the pup. If you interfere with their actions they may not learn to get along with each other.